@JuhaManninen
If you did not have to install any 3rd Party software because you already had all you want, it is great but as I said generally there will be no problem on other distros as well if you stick with what they install.
Problems arise when you want to have other than your distro provides. You may need newer or older version of something. Lets suppose you have a very big old Lazarus project but after your regular update Manjaro upgraded Lazarus to 1.6.4 and its dependancy fpc to 3.0.2 automatically and your project is not compiling anymore. Then what ?
I 've used Slackware, Redhat-Fedora, Debian-Ubuntu-Mint, PCLinuxOS and some others before. None of them was free of dependancy conflicts. I bet you can mess up Manjaro too. Its a Debian derivative too after all.
Anyway, It may not matter if all you do on computer is disposable but it is nice to have controlled environment and using a source version control system if you have any serious project at hand.